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decoding h.264 BP stream on DM3730 DSP

Peter Meerwald
Prodigy 70 points
Other Parts Discussed in Thread: DM3730

Hello,

I'm trying to decode a h.264 BP stream created by a Grandstream GVX3140 on the DSP of a DM3730

problem is that the DSP hangs reproducible after about 270 frames

I've analyzed the h.264 BP stream and extracted two sequences (one that decodes correctly, x.z9_i, and one that fails to decode, x.z10_i)

sequences are available: http://pmeerw.net/x.z9_i and http://pmeerw.net/x.z10_i

I speculate that the DSP decoder does not support SPS or PPS IDs >=  8 -- is this a known issue/limitation?

the working sequence has SPS/PPS ID 7, the failing sequence SPS/PPS ID 8; I see no other relevant difference

the h.264 standard allows for 256 PPS IDs and 32 SPS IDs; other decoders (ffmpeg) decode both sequences correctly

I'm using the tidspbridge interface with gst-dsp; I know, unsupported, but I think the issue is in the DSP blob; my gstreamer pipeline is: gst-launch-0.10 filesrc blocksize=16384 location=x.z10_i ! "video/x-h264" !
dspvdec ! colorspace ! freeze ! ximagesink

thanks, p.

  • 0
    Prodigy 70 points

    Hi,

    I manually fixed up the h.264 bitstream x.z10_i by changing SPS and PPS IDs from 8 to 7 in PPS and SPS NALUs and slice headers (result in at http://pmeerw.net/x.z10_i_corrected) and ... (drumroll) ... it works on the DSP

    so, what to do?

    can the DSP blob be fixed?

    thanks, p.